Bypassing Malware VM Detection: Spoofing a CPU Fan via Custom SMBIOS

Malware often checks for the absence of hardware components typically not emulated in virtual machines (like a CPU fan) to evade analysis. This post details how to bypass this detection by modifying the virtual machine's SMBIOS data to spoof a CPU fan. The author thoroughly explains the steps for Xen and QEMU/KVM environments, including obtaining SMBIOS data, creating a custom SMBIOS file, and configuring the VM. The post also highlights the need to additionally handle SMBIOS Type 28 (temperature probe) data in Xen for successful WMI deception.